#include<fstream>
#include<math.h>
using namespace std;
unsigned int m,n;
int a[17][17],semn[17],maxim;
void citire(unsigned int &n, unsigned int &m)
{ifstream f ("flip.in");
 f>>n>>m;
 for(unsigned int i=1;i<=n;i++)
	 for(unsigned int j=1;j<=m;j++)
		 f>>a[i][j];
 f.close();}
void sum()
{int suma=0;
 for(unsigned int j=1;j<=m;j++) 
	 for(unsigned int i=1;i<=n;i++) {
		 suma+=semn[i]*a[i][j];}
 if(suma>maxim) maxim=suma;}
void back(unsigned int k)
{if(k==n) sum();
 else {
	 semn[k]=1;
	 back(k+1);
	 semn[k]=-1;
	 back(k-1);}}
int main()
{citire(n,m);
 back(1);
 ofstream g ("flip.out");
 g<<maxim;
 g.close();
 return 0;}